Field of the Invention
The present disclosure relates to a developing blade, a developing device, and a cartridge used in an image forming apparatus.
A cartridge described here includes at least one of developer, a developing roller, and a process unit and is detachably attachable to an image forming apparatus main body (hereinbelow, an apparatus main body). An image forming apparatus forms an image on a recording medium using an electrophotographic image forming process. An example of an image forming apparatus includes an electrophotographic copying machine, an electrophotographic printer (a light-emitting diode (LED) printer, a laser beam printer, etc.), a facsimile machine, and a word processor.
Description of the Related Art
An apparatus main body forms an electrostatic image by irradiating a photosensitive drum (an image bearing member) with light corresponding to image data. The apparatus main body supplies developer (hereinbelow, toner) to the electrostatic image from a developing roller (a developer bearing member) of a developing device and develops the electrostatic image as a toner image. The toner image is transferred from the photosensitive drum to a recording material such as recording paper by a transfer device. The toner image is fixed to the recording material by a fixing device, and thus a recorded image is formed. A developing device using toner uses a developing blade for regulating a layer thickness of the toner on the developing roller. In addition, a configuration is discussed for sealing toner by providing a sealing member between the developing roller and a developer container to prevent toner leakage from an end portion of the developing roller.
For example, Japanese Patent Application Laid-Open No. 2016-66077 describes a developing device which includes a developing roller, a developing blade, sealing members which are disposed on both end portions of the developing roller in an axis direction for sealing between the developing roller and a developer container, and a seal pressing member for pressing a side surface of the sealing member. In the developing device, the seal pressing member applies pressing force to the side surface of the sealing member in a direction toward a center of the developing device and deforms the sealing member to attach a side surface opposite to the pressed side of the sealing member to the developing blade.
Accordingly, the sealing members abut on the developing roller on the both end portions of the developing blade in the axis direction of the developing roller to prevent outflow of toner and toner leakage between the developing blade and the sealing member at the same time.
A metal blade of stainless steel and the like may be used as a developing blade in some cases. In this case, a blade thickness is generally 1 mm or less. Thus, it is discussed that the configuration in which the seal pressing member presses the side surface of the sealing member to attach the side surface of the sealing member opposite to the pressed portion to the developing blade as described in Japanese Patent Application Laid-Open No. 2016-66077 is applied to a developing blade using metal. However, when a thin metal blade is used, it was found that the sealing member disposed on a longitudinal end portion was deformed and crawled under the developing blade, and the sealing member was brought into contact with a back surface opposed in a thickness direction to a front surface abutting on the developing roller. The sealing member is brought into contact with the developing blade and urges the developing blade toward the developing roller, and thus an abutting pressure is increased between the developing blade and the developing roller, and a failure of toner circulation is caused. Accordingly, there is a possibility that the toner melts and adheres to the developing blade and causes an image defect.